87 lines
3.4 KiB
Rust
87 lines
3.4 KiB
Rust
//! Panic support for libcore
|
|
//!
|
|
//! The core library cannot define panicking, but it does *declare* panicking. This
|
|
//! means that the functions inside of libcore are allowed to panic, but to be
|
|
//! useful an upstream crate must define panicking for libcore to use. The current
|
|
//! interface for panicking is:
|
|
//!
|
|
//! ```
|
|
//! # use std::fmt;
|
|
//! fn panic_impl(fmt: fmt::Arguments, file_line_col: &(&'static str, u32, u32)) -> !
|
|
//! # { loop {} }
|
|
//! ```
|
|
//!
|
|
//! This definition allows for panicking with any general message, but it does not
|
|
//! allow for failing with a `Box<Any>` value. The reason for this is that libcore
|
|
//! is not allowed to allocate.
|
|
//!
|
|
//! This module contains a few other panicking functions, but these are just the
|
|
//! necessary lang items for the compiler. All panics are funneled through this
|
|
//! one function. Currently, the actual symbol is declared in the standard
|
|
//! library, but the location of this may change over time.
|
|
|
|
#![allow(dead_code, missing_docs)]
|
|
#![unstable(feature = "core_panic",
|
|
reason = "internal details of the implementation of the `panic!` \
|
|
and related macros",
|
|
issue = "0")]
|
|
|
|
use fmt;
|
|
use panic::{Location, PanicInfo};
|
|
|
|
#[cold]
|
|
// never inline unless panic_immediate_abort to avoid code
|
|
// bloat at the call sites as much as possible
|
|
#[cfg_attr(not(feature="panic_immediate_abort"),inline(never))]
|
|
#[lang = "panic"]
|
|
pub fn panic(expr_file_line_col: &(&'static str, &'static str, u32, u32)) -> ! {
|
|
if cfg!(feature = "panic_immediate_abort") {
|
|
unsafe { super::intrinsics::abort() }
|
|
}
|
|
|
|
// Use Arguments::new_v1 instead of format_args!("{}", expr) to potentially
|
|
// reduce size overhead. The format_args! macro uses str's Display trait to
|
|
// write expr, which calls Formatter::pad, which must accommodate string
|
|
// truncation and padding (even though none is used here). Using
|
|
// Arguments::new_v1 may allow the compiler to omit Formatter::pad from the
|
|
// output binary, saving up to a few kilobytes.
|
|
let (expr, file, line, col) = *expr_file_line_col;
|
|
panic_fmt(fmt::Arguments::new_v1(&[expr], &[]), &(file, line, col))
|
|
}
|
|
|
|
#[cold]
|
|
#[cfg_attr(not(feature="panic_immediate_abort"),inline(never))]
|
|
#[lang = "panic_bounds_check"]
|
|
fn panic_bounds_check(file_line_col: &(&'static str, u32, u32),
|
|
index: usize, len: usize) -> ! {
|
|
if cfg!(feature = "panic_immediate_abort") {
|
|
unsafe { super::intrinsics::abort() }
|
|
}
|
|
|
|
panic_fmt(format_args!("index out of bounds: the len is {} but the index is {}",
|
|
len, index), file_line_col)
|
|
}
|
|
|
|
#[cold]
|
|
#[cfg_attr(not(feature="panic_immediate_abort"),inline(never))]
|
|
#[cfg_attr( feature="panic_immediate_abort" ,inline)]
|
|
pub fn panic_fmt(fmt: fmt::Arguments, file_line_col: &(&'static str, u32, u32)) -> ! {
|
|
if cfg!(feature = "panic_immediate_abort") {
|
|
unsafe { super::intrinsics::abort() }
|
|
}
|
|
|
|
// NOTE This function never crosses the FFI boundary; it's a Rust-to-Rust call
|
|
#[allow(improper_ctypes)] // PanicInfo contains a trait object which is not FFI safe
|
|
extern "Rust" {
|
|
#[lang = "panic_impl"]
|
|
fn panic_impl(pi: &PanicInfo) -> !;
|
|
}
|
|
|
|
let (file, line, col) = *file_line_col;
|
|
let pi = PanicInfo::internal_constructor(
|
|
Some(&fmt),
|
|
Location::internal_constructor(file, line, col),
|
|
);
|
|
unsafe { panic_impl(&pi) }
|
|
}
|